LXR linux/tools/perf/tests/backward-ring-buffer.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Test backward bit in event attribute, read ring buffer from end to
   4 * beginning
   5 */
   6
   7#include <evlist.h>
   8#include <sys/prctl.h>
   9#include "record.h"
  10#include "tests.h"
  11#include "debug.h"
  12#include "parse-events.h"
  13#include "util/mmap.h"
  14#include <errno.h>
  15#include <linux/string.h>
  16#include <perf/mmap.h>
  17
  18#define NR_ITERS 111
  19
  20static void testcase(void)
  21{
  22        int i;
  23
  24        for (i = 0; i < NR_ITERS; i++) {
  25                char proc_name[15];
  26
  27                snprintf(proc_name, sizeof(proc_name), "p:%d\n", i);
  28                prctl(PR_SET_NAME, proc_name);
  29        }
  30}
  31
  32static int count_samples(struct evlist *evlist, int *sample_count,
  33                         int *comm_count)
  34{
  35        int i;
  36
  37        for (i = 0; i < evlist->core.nr_mmaps; i++) {
  38                struct mmap *map = &evlist->overwrite_mmap[i];
  39                union perf_event *event;
  40
  41                perf_mmap__read_init(&map->core);
  42                while ((event = perf_mmap__read_event(&map->core)) != NULL) {
  43                        const u32 type = event->header.type;
  44
  45                        switch (type) {
  46                        case PERF_RECORD_SAMPLE:
  47                                (*sample_count)++;
  48                                break;
  49                        case PERF_RECORD_COMM:
  50                                (*comm_count)++;
  51                                break;
  52                        default:
  53                                pr_err("Unexpected record of type %d\n", type);
  54                                return TEST_FAIL;
  55                        }
  56                }
  57                perf_mmap__read_done(&map->core);
  58        }
  59        return TEST_OK;
  60}
  61
  62static int do_test(struct evlist *evlist, int mmap_pages,
  63                   int *sample_count, int *comm_count)
  64{
  65        int err;
  66        char sbuf[STRERR_BUFSIZE];
  67
  68        err = evlist__mmap(evlist, mmap_pages);
  69        if (err < 0) {
  70                pr_debug("evlist__mmap: %s\n",
  71                         str_error_r(errno, sbuf, sizeof(sbuf)));
  72                return TEST_FAIL;
  73        }
  74
  75        evlist__enable(evlist);
  76        testcase();
  77        evlist__disable(evlist);
  78
  79        err = count_samples(evlist, sample_count, comm_count);
  80        evlist__munmap(evlist);
  81        return err;
  82}
  83
  84
  85int test__backward_ring_buffer(struct test *test __maybe_unused, int subtest __maybe_unused)
  86{
  87        int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;
  88        char pid[16], sbuf[STRERR_BUFSIZE];
  89        struct evlist *evlist;
  90        struct evsel *evsel __maybe_unused;
  91        struct parse_events_error parse_error;
  92        struct record_opts opts = {
  93                .target = {
  94                        .uid = UINT_MAX,
  95                        .uses_mmap = true,
  96                },
  97                .freq         = 0,
  98                .mmap_pages   = 256,
  99                .default_interval = 1,
 100        };
 101
 102        snprintf(pid, sizeof(pid), "%d", getpid());
 103        pid[sizeof(pid) - 1] = '\0';
 104        opts.target.tid = opts.target.pid = pid;
 105
 106        evlist = evlist__new();
 107        if (!evlist) {
 108                pr_debug("Not enough memory to create evlist\n");
 109                return TEST_FAIL;
 110        }
 111
 112        err = evlist__create_maps(evlist, &opts.target);
 113        if (err < 0) {
 114                pr_debug("Not enough memory to create thread/cpu maps\n");
 115                goto out_delete_evlist;
 116        }
 117
 118        bzero(&parse_error, sizeof(parse_error));
 119        /*
 120         * Set backward bit, ring buffer should be writing from end. Record
 121         * it in aux evlist
 122         */
 123        err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
 124        if (err) {
 125                pr_debug("Failed to parse tracepoint event, try use root\n");
 126                ret = TEST_SKIP;
 127                goto out_delete_evlist;
 128        }
 129
 130        evlist__config(evlist, &opts, NULL);
 131
 132        err = evlist__open(evlist);
 133        if (err < 0) {
 134                pr_debug("perf_evlist__open: %s\n",
 135                         str_error_r(errno, sbuf, sizeof(sbuf)));
 136                goto out_delete_evlist;
 137        }
 138
 139        ret = TEST_FAIL;
 140        err = do_test(evlist, opts.mmap_pages, &sample_count,
 141                      &comm_count);
 142        if (err != TEST_OK)
 143                goto out_delete_evlist;
 144
 145        if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
 146                pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",
 147                       sample_count, comm_count);
 148                goto out_delete_evlist;
 149        }
 150
 151        evlist__close(evlist);
 152
 153        err = evlist__open(evlist);
 154        if (err < 0) {
 155                pr_debug("perf_evlist__open: %s\n",
 156                         str_error_r(errno, sbuf, sizeof(sbuf)));
 157                goto out_delete_evlist;
 158        }
 159
 160        err = do_test(evlist, 1, &sample_count, &comm_count);
 161        if (err != TEST_OK)
 162                goto out_delete_evlist;
 163
 164        ret = TEST_OK;
 165out_delete_evlist:
 166        evlist__delete(evlist);
 167        return ret;
 168}
 169